An advertiser runs a report at the Campaign level and includes invalid clicks statistics. The report indicates that 20% of clicks received during the selected time period were invalid. This means that the invalid clicks were:

An advertiser runs a report at the Campaign level and includes invalid clicks statistics. The report indicates that 20% of clicks received during the selected time period were invalid. This means that the invalid clicks were: 

A) filtered out of the account before they accrued cost 
B) charged to the account
C) removed as a result of a proactive investigation
D) credited to the account